elementFromPoint not recognising certain elements

Question

I have an issue with which I've been battling for a couple of days now and I cannot understand what the problem is.

I want to fire up an event when a certain element hits the top of my <div>. It works well with most of the elements in my document except one, which incidentally is the one I'm interested in.

They're all span, with different classes. I'm detecting the class with el.classList.contains("myclass"). See my snippet below, with pagenum in the function, which gets picked up (although several times, but that's another minor issue). It works with line, line-group, and pagenum. It doesn't work with mspage.

Can someone tell me please what I am missing?

Thanks.

Update

I just noticed that if I give the mspage elements a height of 2 rem then it does detect them. Ideally I wanted those spans to be invisible to the user, and if I use display:none or visibility:hidden they don't get caught.

document.getElementById('xslt-transformation').addEventListener('scroll', function(e) {

    const el = document.elementFromPoint(this.getBoundingClientRect().x, this.getBoundingClientRect().y);
    if (el.classList.contains("pagenum")) {


            console.log(el.id)

        
    }
}); 

html, body, #mapdiv{
  height: 100%;
  margin: 0;
}

#xslt-transformation {

max-height: 63vh;
overflow: auto;

}

.mspage {
  display: block;
}

.line {
  display: block;
}

.line-group {
  padding: 2rem;
}

.footnotes {
  padding: 1rem;
  display: block;
}

.catchword {
  display: block;
  padding: 1rem
}

.diva-wrapper {
    min-height: 70vh !important;
  }

<div class="tab-pane fade active show" id="transcription" role="tabpanel" aria-labelledby="transcription-tab">
                            <div class="card">
                                <div class="card-body">
                                    <h5 class="card-title">Transcription</h5>
                                    <h6 class="card-subtitle mb-2 text-muted">Your beautiful transcription here</h6>

                                    <div id="xslt-transformation">
                                        

                                    
         
            
<span class="mspage" id="MS Gen 1042_9 003"></span>    
        
            <span class="line-group">
               <span class="line"><del>Latha gan raibh Padric 'na * Mhùr</del></span>
               <span class="line"><del>Cha raibh sailm air ùidh, ach ceol.</del></span>
               <span class="line"><del>Chaidh è thigh Oissain Mhic Fhinn,</del></span>
               <span class="line"><del>O sann leis bu bhinn a ghloir.</del></span>
            </span>
         
            
            <span class="line-group">
               <span class="line">Failt ort fein, a shean-fhir shuairc,</span>
               <span class="line">Air chuairt thugad thainig mi,</span>
               <span class="line">A laoich mhòir <span>***</span> mhìlidh nach meat</span>
               <span class="line">Cha d' eur thu riamh neach mu d'ni.</span>

            </span>
            <span class="line-group">
               <span class="line">Sgeul a b'ait leom fhaotainn uait</span>
               <span class="line">Odha Chuthaill is cruaidh colg,</span>
               <span class="line">An Cath is tinn' a thug an Fhiann</span>
               <span class="line">O na ghineadh tu riamh 'n an lorg</span>
            </span>

            <span class="line-group">
               <span class="line">Dh'innsinn sin duitse gun dàil,</span>
               <span class="line">Dheagh Mhic Ailpein nan salm binn,</span>
               <span class="line">An Cath is tinn' a thug na fir</span>
               <span class="line">O'n a ghin iad Fiannaibh Fhinn.</span>
            </span>

            <span class="line-group">
               <span class="line">Dearmad air † fleadh a rinn Fionn</span>
               <span class="line">Ann  Albuinn ri h àm nan laoch, </span>  
               
       
               <span class="footnotes">Footnotes: * Lùth-chuirt †cuirm, fèisd</span>
               <span class="catchword">Chuir</span>
               
               <span class="mspage" id="MS Gen 1042_9 004"></span>
               
               <span class="pagenum" id="p4">4</span>
               
               <span class="line">Chuir pairt do'n Fheinn fui' struim dearg,</span>
               <span class="line">Dh'eirich orra fearg is fraoch</span>
            </span>
            
            <span class="line-group">
               <span class="line">Tre Chaoilte Mhic Rannachair mhoir</span>
               <span class="line">'S Mac o Dòrain a bhi leinn,</span>
               <span class="line">Mar sud is Àillidh maith ùr</span>
               <span class="line">Thug breiteachd bliadhna ri Mùr Fhinn</span>
            </span>
            
            <span class="line-group">
               <span class="line">Ghluais an trithear a dh'Fhiannaibh Fhinn</span>
               <span class="line">Gu Righ Lochlann nan srian sliom,</span>
               <span class="line">Seirbheis blia'na thug iad dha</span>
               <span class="line">'N trithear a bha 'n ùidh ri h uaill.</span>
            </span>
            
            <span class="line-group">
               <span class="line">Gabh Bann-righ Lochlann nan sgiath donn</span>
               <span class="line">Trom ghaoil trom, 's cha∧<del>'s cha</del> b' ann gu deas,</span>
               <span class="line">Air Àillidh greadhnach nan arm geur</span>
               <span class="line">Gus an d'èirich a cheilg leis.</span>
            </span>
            
            
            <span class="line-group">
               <span class="line">Ghluais i a leabuidh an Righ</span>
               <span class="line">An gniomh mun do dhoirteadh an fhuil,</span>
               <span class="line">Gu hAlbuinn fhlathail nam Fiann</span>
               <span class="line">Thugadar an triath th'air muir.</span>
            </span>
            
            
            <span class="line-group">
               <span class="line">Bha Righ air Lochlann san uair</span>
               <span class="line">Leis am buinnte buaidh is blàr</span>
               <span class="line">Earragan Mac Ainnir nan lonng,</span>
               <span class="line">A Righ bu mhaith a làmh 's a lann.</span>
            </span> 
            

            
            <span class="line-group">
               <span class="line">Chruinnich Righ Lochlann mor shluagh</span>
               <span class="line">Cabhlach cruaidh a dh'fhàs gu treun:</span>
               
               <span class="catchword">Dh'èirich</span>
  
             
               <span class="mspage" id="MS Gen 1042_9 005"></span>
               
               <span class="pagenum" id="p5">5</span>
               
               <span class="line">Dh'èirich sud o'n àirde tuath</span>
               <span class="line">Naoi Righrin, 's an sluagh leis.</span>
            </span> 
            
            
            <span class="line-group">
               <span class="line">Sheol iad air an abhais àrd</span>
               <span class="line">O chòrs Eirinn bu gharg gàir </span>
               <span class="line">Gu h Albuinn fhlathail nam Fiann </span>
               <span class="line">Thogadar an triath th' air muir.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Teachdoireachd thainig∧ thugainn gu luath,</span>
               <span class="line">Sgeula cruaidh chuir ruinn gu geur,</span>
               <span class="line">Còmhrag nam fear Innse-fàil </span>
               <span class="line">Fhaolainn air an tràigh mu dheas.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Thairig Fionn doibh cumha mhòr</span>
               <span class="line">Làn an tunna do'n dearg òr:</span>
               <span class="line">Do Righ Lochlann nan arm sean,</span>
               <span class="line">Araon, agus a bhean fein.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Lochlannaich a bhuithinn bhorb</span>
               <span class="line">Le meud an stoirm as an lèathachd</span>
               <span class="line">Cha ghabh iad cumha fui'm ghrein</span>
               <span class="line">Gun an Fheinn a bhi 'n an dèigh</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Comhairl' eil' a chinn aig Fionn,</span>
               <span class="line">'S aig maithibh na Feinne gu leir;</span>
               <span class="line">Nighean Righ na' n gabht' i uath,</span>
               <span class="line">Gun d'fhuair è sud, 's a bhean fhein.</span>
            </span> 
            
            <span class="catchword">Chuir</span>
            
            <span class="mspage" id="MS Gen 1042_9 006"></span>
            
            <span class="pagenum" id="p6">6</span>
            
            <span class="line-group">
               <span class="line">Chuir sinn 'ga fhios nighean Righ</span>
               <span class="line">Bu ghuirme sùil, 's bu ghrinne meur;</span>
               <span class="line">Chuir sinne ga coimhead ceud each</span>
               <span class="line">A b'fhearr ris an deachaidh srian,</span>
               <span class="line">Le'n ceud marcaich air a' muin</span>
               <span class="line">Fui' chulaibh shròil le'n laste gniomh</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Theirinn i'n sud air n raon,</span>
               <span class="line">'S dh'fhàg i 'na dèigh na h eich,</span>
               <span class="line">Thug i ceum uighe d' an coir</span>
               <span class="line">'S da choinnleir air 'na làimh dheis,</span>
               <span class="line">Da choinneil air ghuaillnibh a guin</span>
               <span class="line">'S dealbh a chrùin o gheug nam port</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Do naigheachds' o phobull Fhinn</span>
               <span class="line">Innis dhuinn a bhri', 's a bheachd?</span>
               <span class="line">Mo naigheachds' o phobull Fhinn</span>
               <span class="line">Gum faigheadh tu bhri' gu ceart;</span>
            </span> 
            
            
            <span class="line-group">
               <span class="line">Mu rinn do bhean ort beairt chli,</span>
               <span class="line">'S gun d'iomair i 'n gniomh gu cearr:</span>
               <span class="line">Thoir cairdeas is comunn do dh'Fhionn</span>
               <span class="line">'S gum faigheadh tu mi 'na geall.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Gheibhe tu sud is ciad seud,</span>
               <span class="line">Is ciad leug o'n uirbhich shaor:</span>
               <span class="line">Gheibhe tu <del>sud</del>ceud seothag suairc'</span>
               <span class="line">Air am bitheadh buaidh nan eun:</span>
            </span> 
            <span class="catchword">Gheibhe</span>
   
            
            <span class="mspage" id="MS Gen 1042_9 007"></span> 
            
            <span class="pagenum" id="p7">7</span>
            
            <span class="line-group">
               <span class="line">Gheibhe tu sud is ciad mias</span>
               <span class="line">Do chùrsa Righ bheath' an àidh,</span>
               <span class="line">'S ge b' è ghleidheadh iad r' a bheo</span>
               <span class="line">Chumadh iad duin' òg a ghnà.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Gheibhe tu sud is ciad greidh,</span>
               <span class="line">Is làn Glinne do chridh bàn</span>
               <span class="line">'S a mhacain mar gabh thu sin </span>
               <span class="line">Thoir leat do bhean, 's thoir dhuinne sith.</span> 
            </span> 
            
            <span class="line-group">
               <span class="line">'Ta cha d'thugainn sith do neach</span>
               <span class="line">Do dh' Àillidh, no ghin d' ar Feinn,</span>
               <span class="line">Ach Fionn fein a thigh 'n fui'm bhreith</span>
               <span class="line">Is a chreach a thoirt gu tràigh.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">'Ta cha d'thug thu leat do neart</span>
               <span class="line">Na bheireadh a chreach gu tràigh:</span>
               <span class="line">Falbhai mis' is beannachd leat,</span>
               <span class="line">O'n chaidh t aithneachd bun os cionn.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Cha'n fahlbh thus' a chiabh na'n cleachd,</span>
               <span class="line">A Ribhinn fharust a bheoil bhinn</span>
               <span class="line">Gheibhe tu na seuda saor,</span>
               <span class="line">'S cheanglainn thu ri m' thaobh deas.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Cha 'n fhan mis' a cheann na'n cliar,</span>
               <span class="line">O nach traogh mi t fhiamh, is t fhearg;</span>
               
               <span class="catchword">'S o</span>
          
               
               <span class="mspage" id="MS Gen 1042_9 008"></span> 
               
               <span class="pagenum" id="p8">8</span>
               
               <span class="line">'S nach faighinn saor fui' m' bhreith</span>
               <span class="line">Ceann na deise bu | ghann ciall </span>
            </span> 
            
            <span class="line-group">
               <span class="line">Cha 'n fhàg mi agaibh do theach</span>
               <span class="line">Do bheinn, no dh' amhuinn, no thulaich;</span>
               <span class="line">Ach Albuinn a thogail leom</span>
               <span class="line">'Na cròchcan glas ann am loinngeas.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Thionndaidh i ris a cùl,</span>
               <span class="line">'S mharcaich i do 'n chùirt gu dian:</span>
               <span class="line">Bu lion' ar sròl 'ga thogail suas,</span>
               <span class="line">'S ann òrdugh gu luath chaidh an Fhiann.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Fhreagair Àillidh 'n  còmhrag cruaidh, </span>
               <span class="line">Do 'n t sluagh a thainig ann gèill.</span>
               <span class="line">Ceann Mhic Nì', Mhic Naomh, Mhic Near,</span>
               <span class="line">Leigeadh leis air an treas beum.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Deich Ceannarda-fichead d'ar Feinn</span>
               <span class="line">'S ceann Àillidh fein air an tùs,</span>
               <span class="line">Thuit sud air laimh Earragainn mhoir</span>
               <span class="line">Man deachaidh na sloigh ann dlùths'.</span>
            </span> 
            
            
            <span class="line-group">
               <span class="line">'N sin chaidh Fionn fein air thùs,</span>
               <span class="line">Deagh Mhac Chuthaill a ghnuis ghil;</span>
               <span class="line">'S deich Ceannard-fichead air a laimh dheis,</span>
               <span class="line">Do shiol Chuthaill na'n cleas lùth.</span>
            </span> 
            <span class="catchword">Labhair</span>
           
            <span class="mspage" id="MS Gen 1042_9 009"></span> 
            
            <span class="pagenum" id="p9">9</span>
            
            <span class="line-group">
               <span class="line">Labhair Fionn flath na'n cuach,</span>
               <span class="line">Ri maithibh uaislibh Innse-fàil;</span>
               <span class="line">Co dh'iongas Earragainn sa ghreis</span>
               <span class="line">Nan leigeamaid leis ar tàir.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">'S ann bha fhreagradh sud aig Goll</span>
               <span class="line">An Sonn a bha deachdair achlaoi.</span>
               <span class="line">D'iongaidh mi Earragainn sa ghreis</span>
               <span class="line">'S bheir mi d'fheuchainn d'a chleas lùithe.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">Mac an Luthaich, 's Diarmad donn,</span>
               <span class="line">An t Oscar mòr, is Mac an Lèig,</span>
               <span class="line">Ga d' dhion o shrith-bhuillean an laoich,</span>
               <span class="line">Cum dithis air gach taobh do d' sgèith.</span>
            </span> 
                         

            <span class="line-group">
               <span class="line">Dolphinne Mac Mhalcain o'n Ghrèig</span>
               <span class="line">* Muime Earragainn, 's cha bi bhreug,</span>
               <span class="line">'N àm sgathach a chinn d' a dhaltadh</span>
               <span class="line">A Ri' mhòir bu do amhluidh iomairt:</span>
               <span class="line">'S mar bhithe mi 's Fionn nam fleadh</span>
               <span class="line">Gum buineadh è 'n ceann do'n chearthar.</span>
            </span> 
            
<span class="footnotes">Footnotes: * Ge d' a tha ùghdar na h eachdrui so  
   a'g radh gum b'e Dolphinne Muime 
   Earragainn, tha 'n leughair r 'a thuig=,
   sinn gur è Oide bha ann. </span>

            <span class="mspage" id="MS Gen 1042_9 010"></span> 
            
            <span class="pagenum" id="p10">10</span>
            
            <span class="line-group">
               <span class="line">Seachd fichead 's mìle sonn</span>
               <span class="line">Thuit le Garadh, 's thuit le Goll:</span>
               <span class="line">Urdal le <del>Oissain an</del> Oscar an àidh,</span>
               <span class="line">'S le Conall, 's le Coireall cneas bhàn.</span>
            </span> 

            <span class="line-group">
               <span class="line">'S air a bhaiste thainig orm</span>
               <span class="line">A <del>Phadric</del>, chleirich a chanas na sailm,</span>
               <span class="line">Thuit leam fein, 's le Fionn nam fleadh</span>
               <span class="line">A cheart choi'-lion ceann ris a chearthar.</span>
            </span> 
            
            <span class="line-group">
               <span class="line">'S mar duine chaidh as am beul airm,</span>
               <span class="line">No chaidh mar cheo do 'n ghrein;</span>
               <span class="line">Do dh'arm Righ Lochlann gu fior</span>
               <span class="line">Cha 'n fhac' iad riamh an tir fein.</span>
            </span>             
            
            <span class="line-group">
               <span class="line">Tuille mor is leith nam Fiann,</span>
               <span class="line">Thuit iad air an t sliabh mu dheas;</span>
               <span class="line">'S ge d' thainig cuid dhinne as </span>
               <span class="line">Cha d' rinn sinn an lath' ud ar leas.</span>
            </span>            
            
 

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